Are pioneer axons guided by regulatory gene expression domains in the zebrafish forebrain? High-resolution analysis of the patterning of the zebrafish brain during axon tract formation

Although the principles of axon growth are well understood in vitro the mechanisms guiding axons in vivo are less clear. It has been postulated that growing axons in the vertebrate brain follow borders of neuroepithelial cells expressing specific regulatory genes. In the present study we reexamined this hypothesis by analysing the earliest growing axons in the forebrain of embryonic zebrafish. Confocal laser scanning microscopy was used to determine the spatiotemporal relationship between growing axons and the expression pattern of eight regulatory genes in zebrafish brain. Pioneer axons project either longitudinally or dorsoventrally to establish a scaffold of axon tracts during this developmental period. Each of the regulatory genes was expressed in stereotypical domains and the borders of some were oriented along dorsoventral and longitudinal planes. However, none of these borders clearly defined the trajectories of pioneer axons. In two cases axons coursed in proximity to the borders of shh and pax6, but only for a relatively short portion of their pathway. Only later growing axons were closely apposed to the borders of some gene expression domains. These results suggest that pioneer axons in the embryonic forebrain do not follow continuous pathways defined by the borders of regulatory gene expression domains, (C) 2000 Academic Press.

Dpp signaling activity requires Pentagone to scale with tissue size in the growing Drosophila wing imaginal disc.

The wing of the fruit fly, Drosophila melanogaster, with its simple, two-dimensional structure, is a model organ well suited for a systems biology approach. The wing arises from an epithelial sac referred to as the wing imaginal disc, which undergoes a phase of massive growth and concomitant patterning during larval stages. The Decapentaplegic (Dpp) morphogen plays a central role in wing formation with its ability to co-coordinately regulate patterning and growth. Here, we asked whether the Dpp signaling activity scales, i.e. expands proportionally, with the growing wing imaginal disc. Using new methods for spatial and temporal quantification of Dpp activity and its scaling properties, we found that the Dpp response scales with the size of the growing tissue. Notably, scaling is not perfect at all positions in the field and the scaling of target gene domains is ensured specifically where they define vein positions. We also found that the target gene domains are not defined at constant concentration thresholds of the downstream Dpp activity gradients P-Mad and Brinker. Most interestingly, Pentagone, an important secreted feedback regulator of the pathway, plays a central role in scaling and acts as an expander of the Dpp gradient during disc growth.

Signal peptide and helical bundle domains of virulent canine distemper virus fusion protein restrict fusogenicity.

Persistence in canine distemper virus (CDV) infection is correlated with very limited cell-cell fusion and lack of cytolysis induced by the neurovirulent A75/17-CDV compared to that of the cytolytic Onderstepoort vaccine strain. We have previously shown that this difference was at least in part due to the amino acid sequence of the fusion (F) protein (P. Plattet, J. P. Rivals, B. Zuber, J. M. Brunner, A. Zurbriggen, and R. Wittek, Virology 337:312-326, 2005). Here, we investigated the molecular mechanisms of the neurovirulent CDV F protein underlying limited membrane fusion activity. By exchanging the signal peptide between both F CDV strains or replacing it with an exogenous signal peptide, we demonstrated that this domain controlled intracellular and consequently cell surface protein expression, thus indirectly modulating fusogenicity. In addition, by serially passaging a poorly fusogenic virus and selecting a syncytium-forming variant, we identified the mutation L372W as being responsible for this change of phenotype. Intriguingly, residue L372 potentially is located in the helical bundle domain of the F(1) subunit. We showed that this mutation drastically increased fusion activity of F proteins of both CDV strains in a signal peptide-independent manner. Due to its unique structure even among morbilliviruses, our findings with respect to the signal peptide are likely to be specifically relevant to CDV, whereas the results related to the helical bundle add new insights to our growing understanding of this class of F proteins. We conclude that different mechanisms involving multiple domains of the neurovirulent A75/17-CDV F protein act in concert to limit fusion activity, preventing lysis of infected cells, which ultimately may favor viral persistence.

The Articulation of Different Life Domains among Female Senior Managers and Their Subjective Well-Being : Focusing on Meaning Constructions in Everyday Life

Work-life issues have become a major concern across Western societies with the objective to promote women's careers and well-being. However, despite growing attempts to increase the number of women in senior management positions in European countries, such as Switzerland, they remain highly underrepresented. Inspired from the cultural approach in psychology, this article focuses on these women's concrete everyday life to understand how they articulate different life domains and how this influences their subjective well-being. A narrative approach based on reflexivity is adopted to analyze women's activity. Results show meaning intertwinements between life priorities that are often conflicting. Two psychological functions are identified: the feeling of control and the letting go of control. Each of these contributes to women's subjective well-being through the use of diversified supports, but their structuring roles appear only in relation to one another. Results are discussed in the light of existing literature and of their implications.

Finding and characterizing Partially Methylated Domains in human haematopoietic cells

DNA cytosine methylation has been demonstrated to be a central epigenetic modification that has essential roles in a myriad of cellular processes. Some examples of these include gene regulation, DNA-protein interactions, cellular differentiation, X-inactivation, maintenance of genome integrity by suppressing transposable elements and viruses, embryogenesis, genomic imprinting and tumourigenesis. This list is increasingly growing thanks to recent advances in genome-wide technologies, like Whole Genome Bisulfite Sequencing (WGBS-Seq). The development of this technology in research has allowed the identification of new features of the DNA methylation landscape that was not possible using previous technologies, like Partially Methylated Domains (PMDs). PMDs have been found in several cell lines, as well as in both healthy and cancer primary samples. They have been described as regions with high variability in methylation levels across individual CpG sites and intermediate methylation levels on average with respect to the genome. Here, we performed an extensive search of PMDs in a big dataset of different haematopoietic primary cells from both myeloid and lymphoid lineages. We found and characterized significant PMDs in plasma B cells, confirming that PMDs are a phenomenon that is restricted to certain differentiated cells. Additionally, we found loci aberrantly hypomethylated in a myeloma sample which overlapped with plasma B cell PMDs. Genome-wide comparison of the myeloma and plasma B cell sample revealed that this is probably also the case for other loci.

Genetic, structural, and molecular insights into the function of ras of complex proteins domains

Ras of complex proteins (ROC) domains were identified in 2003 as GTP binding modules in large multidomain proteins from Dictyostelium discoideum. Research into the function of these domains exploded with their identification in a number of proteins linked to human disease, including leucine-rich repeat kinase 2 (LRRK2) and death-associated protein kinase 1 (DAPK1) in Parkinson’s disease and cancer, respectively. This surge in research has resulted in a growing body of data revealing the role that ROC domains play in regulating protein function and signaling pathways. In this review, recent advances in the structural informa- tion available for proteins containing ROC domains, along with insights into enzymatic function and the integration of ROC domains as molecular switches in a cellular and organismal context, are explored.

Signal peptide and helical bundle domains of virulent canine distemper virus fusion protein restrict fusogenicity

Persistence in canine distemper virus (CDV) infection is correlated with very limited cell-cell fusion and lack of cytolysis induced by the neurovirulent A75/17-CDV compared to that of the cytolytic Onderstepoort vaccine strain. We have previously shown that this difference was at least in part due to the amino acid sequence of the fusion (F) protein (P. Plattet, J. P. Rivals, B. Zuber, J. M. Brunner, A. Zurbriggen, and R. Wittek, Virology 337:312-326, 2005). Here, we investigated the molecular mechanisms of the neurovirulent CDV F protein underlying limited membrane fusion activity. By exchanging the signal peptide between both F CDV strains or replacing it with an exogenous signal peptide, we demonstrated that this domain controlled intracellular and consequently cell surface protein expression, thus indirectly modulating fusogenicity. In addition, by serially passaging a poorly fusogenic virus and selecting a syncytium-forming variant, we identified the mutation L372W as being responsible for this change of phenotype. Intriguingly, residue L372 potentially is located in the helical bundle domain of the F(1) subunit. We showed that this mutation drastically increased fusion activity of F proteins of both CDV strains in a signal peptide-independent manner. Due to its unique structure even among morbilliviruses, our findings with respect to the signal peptide are likely to be specifically relevant to CDV, whereas the results related to the helical bundle add new insights to our growing understanding of this class of F proteins. We conclude that different mechanisms involving multiple domains of the neurovirulent A75/17-CDV F protein act in concert to limit fusion activity, preventing lysis of infected cells, which ultimately may favor viral persistence.

Domains of expansin gene expression define growth regions in the shoot apex of tomato

Expansins are members of a multigene family of extracellular proteins, which increase cell wall extensibility in vitro and thus are thought to be involved in cell expansion. The major significance of the presence of this large gene family may be that distinctly expressed genes can independently regulate cell expansion in place and time. Here we report on LeExp9, a new expansin gene from tomato, and compare its expression in the shoot tip with that of LeExp2 and LeExp18. LeExp18 gene is expressed in very young tissues of the tomato shoot apex and the transcript levels are upregulated in the incipient primordium. LeExp2 mRNA accumulated in more mature tissues and transcript levels correlated with cell elongation in the elongation zone. In situ hybridization experiments showed a uniform distribution of LeExp9 mRNA in submeristematic tissues. When gibberellin-deficient mutant tomatoes that lacked elongation of the internodes were treated with gibberellin, the phenotypic rescue was correlated with an increase in LeExp9 and LeExp2, but not LeExp18 levels. We propose that the three expansins define three distinct growing zones in the shoot tip. In the meristem proper, gibberellin-independent LeExp18 mediates the cell expansion that accompanies cell division. In the submeristematic zone, LeExp9 mediates cell expansion at a time that cell division comes to a halt. LeExp9 expression requires gibberellin but the hormone is not normally limiting. Finally, LeExp2 mediates cell elongation in young stem tissue. LeExp2 expression is limited by the available gibberellin. These data suggest that regulation of cell wall extensibility is controlled, at least in part, by differential regulation of expansin genes.

Two Pine Endo-β-1,4-Glucanases Are Associated with Rapidly Growing Reproductive Structures

Two cDNA clones encoding endo-β-1,4-glucanases (EGases) were isolated from a radiata pine (Pinus radiata) cDNA library prepared from immature female strobili. The cDNAs PrCel1 (Pinus radiata cellulase 1) and PrCel2 encode proteins 509 and 515 amino acids in length, respectively, including putative signal peptides. Both proteins contain domains conserved in plant and bacterial EGases. The proteins PRCEL1 and PRCEL2 showed strong similarity to each other (76% amino acid identity), and higher similarity to TPP18 (73 and 67%, respectively), an EGase cloned from tomato (Lycopersicon esculentum) pistils, than to any other reported EGases. Northern-blot analyses indicated that both genes displayed a similar pattern of expression. The only significant difference was in the level of expression. In situ hybridizations were used to demonstrate that, within differentiating pine reproductive structures, PrCel1 expression was greatest in microsporangia in pollen strobili and near the developing ovule in the seed strobili. Expression was also found in vegetative tissues, especially in regions experiencing cell elongation, such as the elongating region of root tips. Both proteins have an ability to degrade carboxymethylcellulose in vitro. Genomic-blot analysis indicated the presence of a family of EGase genes in the radiata pine genome, and that PrCel1 and PrCel2 are transcribed from distinct one-copy genes.

Fast classification in incrementally growing spaces

[EN]The classification speed of state-of-the-art classifiers such as SVM is an important aspect to be considered for emerging applications and domains such as data mining and human-computer interaction. Usually, a test-time speed increase in SVMs is achieved by somehow reducing the number of support vectors, which allows a faster evaluation of the decision function. In this paper a novel approach is described for fast classification in a PCA+SVM scenario. In the proposed approach, classification of an unseen sample is performed incrementally in increasingly larger feature spaces. As soon as the classification confidence is above a threshold the process stops and the class label is retrieved...

Magnesium-deficient High-fat Diet: Effects On Adiposity, Lipid Profile And Insulin Sensitivity In Growing Rats.

To determine if magnesium deficiency aggravates the effects of a high-fat diet in growing rats in terms of obesity, lipid profile and insulin resistance. The study population comprised 48 newly weaned male Wistar Hannover rats distributed into four groups according to diet, namely, control group (CT; n = 8), control diet provided ad libitum; pair-feeding control group (PF; n = 16), control diet but in the same controlled amount as animals that received high-fat diets; high-fat diet group (HF; n = 12), and magnesium-deficient high-fat diet group (HFMg(-); n = 12). The parameters investigated were adiposity index, lipid profile, magnesium status, insulin sensitivity and the phosphorylation of proteins involved in the insulin-signaling pathway, i.e. insulin receptor β-subunit, insulin receptor substrate 1 and protein kinase B. The HF and HFMg(-) groups were similar regarding gain in body mass, adiposity index and lipid profile, but were significantly different from the PF group. The HFMg(-) group exhibited alterations in magnesium homeostasis as revealed by the reduction in urinary and bone concentrations of the mineral. No inter-group differences were observed regarding glucose homeostasis. Protein phosphorylation in the insulin-signaling pathway was significantly reduced in the high-fat groups compared with the control groups, demonstrating that the intake of fat-rich diets increased insulin resistance, a syndrome that was aggravated by magnesium deficiency. Under the experimental conditions tested, the intake of a magnesium-deficient high-fat diet led to alterations in the insulin-signaling pathway and, consequently, increased insulin resistance.

Leaf-, Panel- And Latex-expressed Sequenced Tags From The Rubber Tree (hevea Brasiliensis) Under Cold-stressed And Suboptimal Growing Conditions: The Development Of Gene-targeted Functional Markers For Stress Response.

Hevea brasiliensis is a native species of the Amazon Basin of South America and the primary source of natural rubber worldwide. Due to the occurrence of South American Leaf Blight disease in this area, rubber plantations have been extended to suboptimal regions. Rubber tree breeding is time-consuming and expensive, but molecular markers can serve as a tool for early evaluation, thus reducing time and costs. In this work, we constructed six different cDNA libraries with the aim of developing gene-targeted molecular markers for the rubber tree. A total of 8,263 reads were assembled, generating 5,025 unigenes that were analyzed; 912 expressed sequence tags (ESTs) represented new transcripts, and two sequences were highly up-regulated by cold stress. These unigenes were scanned for microsatellite (SSR) regions and single nucleotide polymorphisms (SNPs). In total, 169 novel EST-SSR markers were developed; 138 loci were polymorphic in the rubber tree, and 98 % presented transferability to six other Hevea species. Locus duplication was observed in H. brasiliensis and other species. Additionally, 43 SNP markers in 13 sequences that showed similarity to proteins involved in stress response, latex biosynthesis and developmental processes were characterized. cDNA libraries are a rich source of SSR and SNP markers and enable the identification of new transcripts. The new markers developed here will be a valuable resource for linkage mapping, QTL identification and other studies in the rubber tree and can also be used to evaluate the genetic variability of other Hevea species, which are valuable assets in rubber tree breeding.

Role Of The Different Sexuality Domains On The Sexual Function Of Women With Premature Ovarian Failure.

Women with premature ovarian failure (POF) often manifest complaints involving different aspects of sexual function (SF), regardless of using hormone therapy. SF involves a complex interaction between physical, psychological, and sociocultural aspects. There are doubts about the impact of different complaints on the global context of SF of women with POF. To evaluate the percentage of influence of each of the sexuality domains on the SF in women with POF. Cross-sectional study with 80 women with POF, matched by age to 80 women with normal gonadal function. We evaluated SF through the Female Sexual Function Index (FSFI), a comparison between the POF and control groups using the Mann-Whitney test. Component exploratory factor analysis was used to assess the proportional influence of each domain on the composition of the overall SF for women in the POF group. SF was evaluated using FSFI. Exploratory Factor Analysis for components was used to evaluate the role of each domain on the SF of women with POF. The FSFI score was significantly worse for women with POF, with a decrease in arousal, lubrication, orgasm, satisfaction, and dyspareunia. Exploratory factor analysis of SF showed that the domain with greater influence in the SF was arousal, followed by desire, together accounting for 41% of the FSFI. The domains with less influence were dyspareunia and lubrication, which together accounted for 25% of the FSFI. Women with POF have impaired SF, determined mainly by changes in arousal and desire. Aspects related to lubrication and dyspareunia complaints have lower determination coefficient in SF. These results are important in adapting the approach of sexual disorders in this group of women. Benetti-Pinto CL, Soares PM, Giraldo HPD, and Yela DA. Role of the different sexuality domains on the sexual function of women with premature ovarian failure. J Sex Med 2015;12:685-689.

Internal stresses and textures of nanostructured alumina scales growing on polycrystalline Fe(3)Al alloy

The evolution of internal stresses in oxide scales growing on polycrystalline Fe(3)Al alloy in atmospheric air at 700 degrees C was determined using in situ energy-dispersive synchrotron X-ray diffraction. Ex situ texture analyses were performed after 5 h of oxidation at 700 degrees C. Under these conditions, the oxide-scale thickness, as determined by X-ray photoelectron spectroscopy, lies between 80 and 100 nm. The main phase present in the oxide scales is alpha-Al(2)O(3), with minor quantities of metastable theta-Al(2)O(3) detected in the first minutes of oxidation, as well as alpha-Fe(2)O(3). alpha-Al(2)O(3) grows with a weak (0001) fiber texture in the normal direction. During the initial stages of oxidation the scale develops, increasing levels of compressive stresses which later evolve to a steady state condition situated around -300 MPa. (C) 2010 International Centre for Diffraction Data. [DOI: 10.1154/1.3402764]

Radial variation of anatomical features, wood density and decay resistance in teak (Tectona grandis) from two qualities of growing sites and two climatic regions of Costa Rica

The objective of this study was to show the radial variation of some anatomic characteristics, wood density and natural durability of teak (Tectona grandis L.F.) growing in Costa Rica. Samples of trees 13 years old were obtained from two growing sites (high and low growing) of plantations established in a humid tropical climate (CHT) and dry tropical climate (CST). The variables measured of the fibers as well as for the rays were not affected by the climate or the type of growing site, except for the length of the fibers. The fibers of teak wood from the best growing site were significantly larger. Vessels were found with a greater frequency for the CST but mostly solitary in comparison with the CBT. Average density, maximum density and the variation within the ring presented a light higher magnitude for the CST. The quality of the growing site did not affect these variables. The resistance of fungus attack was similar in the area of heartwood near the pith compared to the heartwood near the sapwood for all the conditions evaluated. Nevertheless, it was observed in some trees a similar resistance of fungus attack for areas of sapwood compared to similar areas of heartwood.